The National Rifle Association is a “paper tiger” despite its much-vaunted reputation for political and lobbying clout, asserts a report released Tuesday by Sen. Christopher S. Murphy.

“This isn’t your father’s NRA,” the Connecticut Democrat said during a telephone press conference. “And the fact is, if the NRA was able to once put a scare into members of Congress, it shouldn’t any longer. It doesn’t win elections like it used to.”

Murphy released the report on the eve of a Senate gun violence hearing scheduled for Jan. 30, and as Congress considers proposed gun restrictions after the Dec. 14 mass shooting at Sandy Hook Elementary School in Newtown, Conn. It is the first in a series of reports that Murphy said will scrutinize the NRA.

Murphy said his goal is to debunk “the continuing mythology about the power of the NRA” and to convince his colleagues on both sides of the aisle that “there is nothing to fear” from the NRA. He pointed to a Sunlight Foundation analysis showing that the NRA’s PAC spent more than $11 million in the 2012 elections but enjoyed a less than 1 percent return on its investment. Sunlight determined that many of the races in which the NRA spent the most money did not go its way.

NRA officials did not return calls seeking comment, but in an advance copy of the testimony he will deliver to the Senate Judiciary Committee on Wednesday, NRA Executive Vice President and CEO Wayne LaPierre invoked the 4.5 million “moms and dads and sons and daughters” who the group counts as active members. About 250,000 of those members have signed up in the months since the Sandy Hook shooting.

The NRA spent $2.2 million on lobbying last year, and more than $24 million on the recent election through its PAC and its lobbying arm, according to the Center for Responsive Politics. The group’s size and grass-roots lobbying heft have helped beat back proposed gun restrictions at the state level, said Robert Cottrol, a law and history professor at George Washington University.

“I would be very cautious” about dismissing the NRA, Cottrol said, noting that Democrats leveled similar charges before enacting an assault weapons ban two decades ago, only to see Republicans seize House control in 1994. “Because essentially we heard the same drumbeat in ’92, ’93 and ’94, and it turned out to be totally false.”

Cottrol called Murphy’s report “a political tactic on the part of those who are supporting greater gun restrictions. If you can say the NRA cannot punish its enemies, it’s a paper tiger, then more members of Congress would be willing to enact gun legislation.”

But on Tuesday’s call, Murphy and Mark Glaze, director of the gun safety coalition Mayors Against Illegal Guns, argued that the Sandy Hook shooting has changed the political calculus. Glaze noted that well-financed new groups, including a national initiative spearheaded by former Rep. Gabrielle Giffords, D-Ariz., and her husband, Mark Kelly, have set out to counter the NRA. Giffords was injured in a Tucson shooting in 2011. Her PAC, Americans for Responsible Solutions, has set out to raise $20 million.

“The perception of power is power, and the NRA is principally a marketing organization” peddling fear, Glaze said. He added that the NRA’s political budget has lost relative impact in the wake of the Supreme Court’s Citizens United v. Federal Election Commission ruling to deregulate political spending.

“The campaign finance world and the issue campaign world changed after Citizens United,” Glaze said. “The end result is that what the NRA spends in almost all races is now a comparative drop in the bucket.”

President Barack Obama has called on his new grass-roots group, Organizing for Action, to support his proposed package of sweeping gun restrictions with calls to Capitol Hill. But in a twist that may reflect the NRA’s enduring power, Obama’s group has reportedly been unable to register a domain name. The domain name organizingforaction.net, for one, is already taken, the Los Angeles Times reported — by none other than the NRA.